Controls for electric welding apparatus



Dec. 22, 1942. A. a, soNNEBoRN 2,305,591

CONTROLS FOR ELECTRIC WELDING APPARATUS Filed Oct. 26, 1938 2 Sheets-Sheet l 5o urc e of lll Il lll l.

Dec. 22, 1942. A. B. soNNEBoRN CONTROLS FOR ELECTRIC WELDING APPARATUS Filed Oct. 26, 1938 2 Sheets-Sheet 2 RNEY.

Patented Dec. 22, 1942 coN'rnoLs Foa ELECTRIC Wnmmdl APPARATUS Arthur B. Sonnebom Detroit, Mich., assignor to The Clark Controller Ohio, a corporation of Ohio Application Jctober 26, 1938, Serial No. 237,030

i4 claims.

This invention relates to electric welding apparatus and to controls therefor.

In welding apparatus of the type comprising a welding machine having electrodes which are engaged by pressure with work to be welded, and through which electrodes and work,*timed electric welding current is passed to effect aweld at the work, it has been founddesirable in many in pressure-engagementwith 'the work for a time period after the interruption of the welding current, in other words, for a cold-hold time period;

To provide improved means for timing the frequency at which successive welds may be made, or, for timing a predetermined delay between successive welds;

To provide an improved construction of delayed operation timing device;

To provide an improved construction of delayed operation pneumatic valve device;

To provide improved means by which the time period during which the welding machine electrodes remain engaged with the work after the welding current ceases to iiow, and the time` period -of delay, or frequency between successive welds, may be' adjusted, one independently ofthe other;

To provide improved meansfor insuring that the electrodes of the welding machine lwill have 4been released from the work and again engaged with the work before a succeeding impulse oi welding current occurs.

Other objects will be apparent to those skilled in the art to which my invention appertains.

My invention -is fully disclosed in the following description taken in connection with the: accomjpanying drawings in which;

Fig. 1 is a. diagrammatic view illustrating an embodiment of my invention;

Figs. 2, 3 and 4 are fragmentary views similar 'cylinder 1 and also Company, Cleveland,

cold-hold delayed operation or time interval device oi that figure;

Fig. s is a longitudinal sectionai view to en-l larged scale of parts shown partly in section and partly in elevation in Fig. 1.

Referring to Fig.l of the drawings, L have shown generally at I a welding machine o! the type comprising stationary upper and lower heads 2 and 3.. the lower head being arranged to support work I to be welded. A lower or stationary electrode is associated with the lower head l and a reciprocable electrode t with the upper head 2. A pneumatic cylinder 1 is supported on the upper `head 2 and has reciprocable therein a piston i connected by a piston rod 9 with the electrode 6, the piston being arranged to be feciprocated downwardly by iluid pressure, such as compressed air, in the 'cylinder 1 above the piston 'and to be restored upwardly by a spring IIl in the cylinder.

y Fluid pressure is supplied to the cylinder 1 from a source of iluid pressure Il, which source may be considered as comprising a storage tank in which fluid, such as air, is stored under pressure by any suitable pressure supplylns means.

Illustrated generally at l2 is a magnetic yalve comprising an outer stationary cylindrical portion Il and a valve element Il reciprocable in a suitable bore therein. the valve element Il having transverse ducts I5 and I6, the duct l! inthe normal position of lthe valve illustrated being aligned with an exhaust the latter communicating with a conduit I9 connected to a conduit 2l communicating with the l.

cylinder 1 above the piston l whereby to exhaust the same and the conduit 20.

The duct I6 of the valve element is normally aligned with an exhaust duct 2i and a duct 22 duct 23 which in turn communicates with 'a conduit 2l connected to the exhausting the cylinder 1;

in this connection it may be stated that the conduit 2| leading to parts to be described may .be of considerable length quick operation oi the parts oi the system, as will be more clearlyl understood hereafter. both .exhausts at l1 and 2| are desirable.k

The valve element Il is arranged tobe moved upwardly by a magnetic plunger 25, andan electro-magnetic winding 2i associated with it, t against the tension o! a spring 21 and thereupon the duct I5 is' moved' out of alignment with the duct I1 ,and'closes the exhaust thereat, and the duct It is moved upwardly to align the duct 2l` Ato a. part of Fig. 1 iiiustrating modifications of a: fw withv a-duct 28. Fluid pressure, from the source duct l1 anda duct ll,-

and that to insure then flows by a conduit 29 through the ducts 23, I3, 23 to the conduit 24 and thence to the cylinder 1 to operate the electrode 5 as described.

After the electrodes have thus been engaged with the work, a pair of electric contacts 33-33 are moved by means to be described into engagement with a corresponding pair o! contacts 3|-3I and electric current lows from a current supply main 32, by a wire 33 to one of the contacts 3|, thence through the contact 33 and a contacter arm 34 through the primary 35 of a transformer, back by another'contactor arm $5 to the other contact 33 and thence to the other contact 3|, and back by a wire 31 to'the other supply main 33.

Current in the secondary 39, of the transformer, is conducted by wires 43 and 4| to the electrodes and 5 respectively to' effect a weld at the work 4.

'I'he means-for operating the contacts 33 and 3| will now be described.y

At 42 is a panel upon which is mounted a frame 43 having lateral arms or brackets 44 and 45. A plunger 45 reciprocates in a bore 41 in the bracket 44 and at its lower end has a reduced diameter portion 43 functioning as a piston rod reciprocating in a bore 49 in the bracket 45, the reduction of diameter providing a down stop 53 for the plunger 45 upon the lower bracket 45.

A valve housing 5| is secured to the bracket 45, preferably by screw threads 52 on the housing threaded into corresponding threads on the bracket. The valve housing 5| is provided with a cylinder 53 within which reciprocates a piston 54 connected to the said piston rod 43.

'Ihe arrangement of the parts within the valve housing 5| will now be briey described with reference to Figs. 1 and 5, this arrangement being more fully illustrated and described in the copending application of Charles H. Rippl, Serial its upper end and this end is normally held in sealing engagement with the open end of the duct 53, by a spring 32 in the valve abutting at opposite ends upon the upper closed end oi' the valve and upon ar tubular screw 33 adjustably threaded into a thimble 54 which in turn is threaded into the lower end of the bore 55.

When fluid pressure communicated to the duct 55, as will be described, is of suillcient value, it forces the valve 63 down against the tension of the spring 32. As soon as the end of the duct 3| is uncovered, the full area of the valve is exposed to the pressure and the valve moves with a positive quick action to a lower position in which' its upper end uncovers an annular chamber 55 in the cylinder wall.

'I'he chamber 55 communicates by a duct 35 with a bore 51 the upper end of which is reduced to form a valve seat 51 continuing into a duct 33 opening into the cylinder 53.

A needle valve 39 threaded into and sealing the bore 51 adjustably controls flow to the duct 53.

The chamber 55 also communicates by a duct 13 with a bore 1| opening at its upper end into a reduced diameter exhaust duct 12 opening into the cylinder 53. A ball check valve 13 closes the duct 12 being held in closing position by a spring 14 abutting at opposite ends on the ball valve and on an adjusting screw 15 threaded into the bore 1|.

The skirt wall of the valve 63 has one or more ports 16 therein, which, with the valve in its normal upper position are aligned with an annular chamber 11 in the wall of the cylinder 55; and th'e chamber 11 communicates by a duct 13 with the bore 1|, the upper end of the screw 15 adjustably overlapping the entrance to the duct 13.

To avoid premature operation of the valve 33 by leakage around the upper end of the valve, into the space at 19 provided by the reduced diameter of the end 5|, a bleeder duct 33 exhausting to atmosphere at 3| is provided.

The screws 33, 15 and 59 are all adjustable and can be locked in adjustment by nuts respectively.

In operation of the parts in the housing 5|, when pressure in the conduit 59, which is a rising pressure supplied 'by the conduit 23 as will presently appear, attains a predetermined value for which the spring 32 in the valve 53 is adjusted, this pressure in the duct 5B moves the valve down, thereby communicating the pressure to the duct 36 and, past the needle valve 59 to the duct 53 and cylinder 53 which moves the piston 54 and plunger 45 upward. Pressure is also communicated to the under side of the ball check valve 13 by the duct 13 to keep the duct 12 closed. When pressure in the conduit 59 and duct 53 is relieved, relieving the pressure in the cylinder 53. the valve 63 resets to its upper position and the iiuid from the cylinder 53 ilows or exhausts out through the conduit 12 displacing the valve 13, into the bore 1|, duct 13, ports 15 into the valve and out through the screw 53.

The rate oi.' upward movement of the plunger 43 is adjusted by the needle valve 39, and the rate of return by the screw 15. 'I'he return movement of the plunger is eiected by a spring 35 aided by gravity, the spring abutting at opposite ends on a bar 33 on the upper end of the plunger and on an arm 31 on the frame 43.

'I'he plunger carries a cam 33 having a cam surface 39. A roller 93 in the nature of a cam follower is mounted on a finger 9| pivoted, as at 92, to an arm 93, the finger being constrained to rotate clock-wise against a stop 94 by a spring 35. The arm 93 is mounted on a shaft 93 supported at one end in a bearing 91 on the bracket 45 and at the other end in another bearing 93 supported in any suitable manner.

By this means, when the plunger 43 is reciprocated upwardly, the cam surface 33 engages the roller 9| causing it to roll over the cam face and thereby rock the arm 93 clockwise, which in turn rocks the contactor arms 34 and 35 clockwise to engage the contacts 33 and 3|.

Continued movement oi.' the cam 33 causes it to' leave the roller 93 and thereupon the arm 93 is rocked in the counter-clockwise direction by a. spring 99 abutting at one end upon the frame '43 and at the other end upon a threadedly adjustable stop |33 on the arm, the counter-clockwise position of the arm being determined by a stop |3| engaging the panel 42.

As will now be clear, as the plunger 45 moves upwardly the contacts 33 and 3| will first be closed and then as it moves farther will open again, the time interval during which they remain closed being determined by the velocity of the plunger 46, which is adjustable by adjusting the rate of admission of air to the cylinder 63 through the duct 88, by the screw valve 69.

When .air is exhausted from the cylinder 53 and the plunger 46 moves downwardly as described, the cam 88 engages the roller 90 and rocks it around the pivot 92 compressing the spring 95 until after the cam has passed beyond the roller whereupon it snaps back to the position illustrated, so thaton the downward movement of the plunger 46 the arm 93 is not rocked but remains inert.

- For slow movements of the plunger 46 and relatively -long impulses of welding current, the roller 90 remains in contacty with the cam surface 89. At greater velocities, for shorter time intervals of current, the roller 90 will be kicked away from the cam face due to the inertia of the parts, and this kinetic energy may be determined by a weight |02 on the arm 93 below the shaft 96, the inertia of the weight tending to hold the arm in the clockwise direction and the spring 99 tending to rotate it.

This part of the subject matter of this case is more fully set forth in the co-pending application of Edward G. Beiderman, Serial Number 84,981, filed June 13, 1936, for improvements in Time controlled electric switches, now Patent No. 2,196,488, dated April 9, 1940.

The said bar 86 upon the upper end of the plunger 46, when the plunger moves up, engages a stop |03 preferably in the form of a pair of lock nuts, on a stem |04 of a valve |05, reciprocatingin a bore |06 in a block |01 mounted on the frame 43.

'I'he positions of the valve are determined by flanges |08 and |09 repectively on the upper and lower ends of the valve engageable with the upper and lower sides of the block |01.

The valve is provided with a reduced diameter neck H which in the lower position of the valve illustrated is aligned with a duct and an exhaust duct H2, and which, when in the upper position of the valve is aligned with a duct H3 and a duct H4. A duct H6 communicates with the ducts and H4. Needle valve screws H6 and H1 are provided controlling the effective size of the ducts and H4 respectively. The valve is moved downwardly when the plunger 46 returns by a spring H8 disposed around the stem |04 and `between the bar 86 and the ilange |08 of the valve.

Illustrated generally at H9 is a delayed operation device comprising a cylinder in which reciprocates a piston |2| connected to piston valve portions |22 and |23 spaced from the piston |2| and from each other by reduced diameter necks |24 and |25.

A stem |26 projecting upwardly from the valve portion |23 carries a stop |21 preferably in the form of lock nuts threaded on the stem |26 by which the position of the parts in the cylinder |20 may be longitudinally adjusted.

A spring |28 normally holds the piston downwardly to its stopped position.

Above the device |9 is a pair of pivoted auxiliary contact arms |29 and |30 normally engaged by springs |3| and |32 with contacts` |33 and |34.and arranged to be rocked to disengage the contacts by upward movement of the stemv |26, in succession, the upper end of the stem being adjacent to the arm |29 and rocking it after a short preliminary movement of the stem, and the arm |23 carrying an adjustable screw |35 movable subsequently into engagement with the arm |30 to rock it.

Description of parts not hitherto given vwill now be given inl connection with a description of the apparatus as a whole. y

To eilect a welding operation, an operator closes a normally open operators contactor |36. If a single welding operation is performed, he momentarily closes the contactor, and-if a succession of welding operations is to be made he holds it closed. When the operator closes the contactor |86, current flows from a current supply line |38 by a wire |31 through the winding |89 of a relay or electro-magnetic contactor, thence by a wire |40 through the contactor |36 to the contact |33 through the arm |29 and by a wire |4| to the other supply main |42. The relay thus operated makes a'maintaining circuit for itself by closing contacts at |43 whereby current flowing through the winding |39 may ilow through the contacts at |43 and by a wire |44 to the contact |34 through the arm |30 and by a wire |45 directly to the said other supply main |42, thereby holding the relay closed, although the operator may have released the contactor |36.

It will be observed from the foregoing connections that the closing circuit for the relay is on the contact |33 and the maintaining circuit therefor is on the contact |34.

Operation of the relay also closed contacts at |46 whereupon current flowed vfrom the supply main |38 through the contacts at |46 through the winding 26 of the magnetic valve l2 and back to the other supply main |42, thereby operating the valve in the manner described by raising the valve element |4. This, as described, supplies fluid pressure from the source H to the cylinder 1 of the welding machine causing the electrode 6 to be moved downwardly to engage the work 4 between the electrodes 6 and 5.

As is well known, fluid pressure thus supplied from the cylinder 1 expands therein so that the pressure in the conduit 20 which communicates with the cylinder will be a gradually rising pressure, and it will only be after the electrodes 5 and 6 have been fully engaged by pressure with the work and the pressure has risen to a value at which a suitable weld may be made, that the pressure in the conduit 20 communicating with the conduit 59 will have risen to the value at which the fluid will be admitted through the duct 68 to the cylinder 63. When, however, the pressure has thus risen the pressure in the cylinder 53 will move the plunger 46 upwardly and operate the arm 93 and the contactor arms 34 arid 36 to send a welding current impulse to the electrodes 6 and 6, as described above.

The plunger 48 when it moves upwardly moves the valve |05 upwardly as described until the neck H8 is aligned with the ducts H3 and H4. Thereupon fluid pressure from the source ilows by a conduit |41 to the duct H3, around the neck H0 of the valve in its upper position to the duct H4, passing the needle valve H1, through the duct H5 into a conduit |48 and thence to the cylinder |20 below the piston |2|.

The rate of flow of this fluid pressure is controlled by the adjustment of the needle valve H1, and the uid pressure moves the piston |2| upwardly carrying with it the piston valve por tion |23. In the normal position of this piston portion it covers and closes a -pair of aligned ducts |43 and |53, the duct |50 being an exhaust duct communicating with atmosphere and the duet |49 being connected to the conduit 59.

When the piston valve portion |23 therefore is moved upwardly sufliciently far, and after a time interval, it uncovers the ports |43 and |53 and opens an exhaust to atmosphere for the cylvinder 53, through the conduit 59, the exhaust -air fiowing around the valve neck |25,

When the piston |2| started to move upwardly and after a. short initial movement, it rocked the switch arm |29 to disengage the contact |33, whereby even if the operators contactor |35 had been maintained closed for a repeat operation, the relay winding |39 would be energized through the maintaining contacts |34. As the piston |2| moves upwardly and reaches the point in its stroke at which exhaust occurs at the duct |50, the screw |35 engages the arm |30 and rocks it out of engagement with contact |34, de-energizing the rel-ay winding |39 and opening the contacts at |43, allowing the magnetic valve I2 to reset and exhaust the cylinder 1 at the duct 2|, as described above, restoring the electrodes and 3 out of engagement with the work. The exhaust eiected at the duct |50 by the piston |2| relieves v relieved, the spring |23 starts the piston |2| downwardly, exhausting the fluid in the cylinder outwardly through the conduit |43, through the duct ||5 past the needle valve ||3 into the duct around the neck ||0 to the exhaust duct ll2, the rate of downward movement of the piston |2| being determined by'the adjustment of the needle valve H6.

As the piston moves downwardly it first reengages the arm |20 with the contact |34 and finally at, or near, the end of its down stroke engages the arm |29 with the contact |33. Ii'

at this time, the contactor |33 has been maintained closed, the parts, which are all in their original restored condition, operate to go through another cycle of operations, but if the contactor |33 has been left open, the parts remain at rest. As will be clear from the foregoing description,

the delayed -upward movement of the piston |2| of the device I9, which movement is determined by the adjustment of the screw ||1, determines the length of the cold-hold period, during which the electrodes 5 and 5 remain engaged with the work after the welding current has been cut off;

and that the downward movement of the piston |2|, the rate of which is determined by the adjusting screw ||3 determines the length of the period which must elapse before another welding operation can be performed, that is to say, the possible frequency of successive operations.

It is desirable, of course, that the exhaust effected by the device ||9 at the duct |50 and the opening of the contact |34 will occur substantially simultaneously, and this will be effected with a relatively rapid movement of the piston |2|, that is to say, on short cold-holds. For long cold-holds, this can also be accomplished by the device ||9 if the parts are carefully adjusted.

When it is not desired to requirev a close adjustment, the arrangement illustrated in Figs. 2, 3 and -i may be employed.

Referring to Fig. 3 the delayed operation device illustrated therein is generally similar to that illustrated at ||9, in Fig. 1, but is arranged not to operate untilr an operating pressure has been obtained at which it will quickly, and with a Jump action, operate its full stroke. A cylinder |5| is provided to which fluid pressure is admitted by a duct |53. A piston |53 in the cylinder has a reduced diameter portion |54 lcovering and sealing the duct |53. Connected to the piston is a cylinder valve portion |55, covering and closing aligned ducts |53 and |51, the duct |51 opening to atmosphere. The .duct |53 communicates with the above described conduit 59. The stem |25, stop |21 and spring |23 of the form of Fig. i are reproduced. Below the duct |55 is a chamber |59 into the lower end of which the said conduit |43 communicates by a duct |52.

In the operation of this form, when the valve |05 of Fig. 1 is operated and the source pressure is adjustably communicated to the conduit |43, this pressure accumulates in the chamber |59 of Fig. 3 while thetime interval is running, the rate of accumulation being determined, as will be understood, by the adiusting screw ||1, Fig. 1. When sufficient pressure has accumulated in the chamber |59, the pressure on the lower end |54 of the piston |53 in the duct |53 becomes sumcient to overcome the spring |23 and the piston starts to rise and immediately the full area of the lower end of the piston |53 is exposed to the pressure, and it moves its full stroke upwardly with a quick jump action, effecting exhaust at the duct |51 and operating the auxiliary contact arms |23 and |30 as described.

In Fig. 4, is illustrated a similar arrangement having a cylinder |50 and a piston valve |5| therein arranged to move upwardly to open an exhaust duct |52 aligned with a duct |53 which communicates with the conduit 59, the stem and |21 and spring |23 being provided as before.

The cylinder opens downwardly into a large chamber |54 communicating with the conduit With this form when the valve |05, of Fig. l, is lifted, and fluid pressure is communicated to the conduit |43, it accumulates in the chamber v|34 and when the pressure thereof on the lower end of the piston |3| reaches a valuesuilicient to overcome the spring |23 and the piston |5| therefore ,starts to move upwardly, it will continue to -move with a relatively rapid motion throughout sumcient stroke to open exhaust at |52 and open the contacts |33 and |34 by the stem |25, as described above, the displacement of space in the cylinder |34 by the moving piston |3| being small relative to the volumetric capacity ofthe chamber |34.

In both the forms of Figs. 3 and 4, the time interval is obtained by the accumulation ofv pressure in the chambers |59 and |54 which in turn is determined by the adjustment at the screw I1, of Fig. 1.

In the modification of Fig. 2, a cylinder |54 is provided in which reciprocates a piston and a valve |54. thestem 35, stop 99 and spring |35, of Fig. l, being reproduced.

The valve |05 and associated parts are substantially the same as shown in Fig. 1, except that an additional duct |51 is provided communicating with the duct ||4 and with a conduit |35 leading to an annular chamber surrounding the middle part of the piston |55.

' minedtime interval l|65 is arranged to uncover anexhau'st port |10.

In the operation of this modincation, when theA valve is operated, as described in connection with the form of Fig. 1, source fluid pressure'in. the conduit |41 is communicated to the conduit |48 and thence to the cylinder |64 and the piston |65 moves upwardly at a retarded rate determined by the adjustment of the screw 81. After a time interval, the piston |65 begins to uncover the annular chamber |69 and thereupon source fluid pressure flows from the conduit |41 'around the valve |05 to the duct ||4', thence to the duct |61 and conduit |68 into the chamber |69 and under the piston |65.

This fiow of source fluid pressure being unrestricted given an instantaneous upward thrust to the valve |66, causing it to move with a quick jump action and cover the exhaust port |18, at the same time, operating the auxiliary contact arms |28 and |30 for the purposes described.

When the valve |05 has been returned downwardly to the position illustrated, fluid pressure is cut off ward movement of the piston |65 is determined by the exhaust of fluid through the conduit |48 and past the needle valve ||6, as described above.

I claimz.

l. In an electro-fiuid-pressure system; an apparatus havingan electrically energizable circuit and a fluid pressure operable element, electric contactor means comprising a fluid pressure movable elementv vmovable to close and after a preof electric` current, a source of fluid pressure, an apparatus having an electrically energizable circuit and a fluid pressure movable element, an electrically operated valve and conduit means controlled thereby.` for communicating source fluid pressure to the apparatus element, electric contactor means comprising a movable element movable to close and after a predetermined time interval of movement to open the energizing circuit, fluid pressure operated timing means controlling energization of the valve to maintain it from the conduit |68 and the downy determined-time interval of movement to open the energizing circuit, timing means and means associated therewith controlling communication of fluid pressure to the apparatus element, to maintain it operated for a predetermined time interval after opening of and means responsive to movement of the contactor element to actuate the timing means.

2. In an electro-fluid-pressure system, an apparatus having an electrically energizable circuit and a fluid pressure movable element, electric contactor means comprising a fluid pressure movable element movable to close and after a predetermined time interval of movement to open the energizing circuit, fluid pressure operable timing means and means associated therewith controlling communication of fluid pressure to the apparatus element to maintain it moved for a predetermined time interval after opening of the energizing circuit, means controlled thereby operated by movement of the contactor element to admit fluid pressure from the source to the timing means.

3. In an electro-fiuid-pressure system, a source of electric current, a source of fluid pressure, an apparatus having an electrically energizable circuit and-a fluid pressure movable element, an electrically operable valve and conduit means controlled thereby for communicating source pressure to the apparatus element to move it, electric contactor means comprising a movable element movable to close and after a predeterof movement to open the energizing circuit, timing means controlling energization of the valve to maintain the apparatus element moved for a predetermined time interval after opening of the energizing circuit and means responsive to movement of the contactor element toactuate the timing means.

4. In an electro-fiuid-pressure system, a source valve means and conduity the energizing circuit,

operated for a predetermined time interval after opening of the'energizing circuit, valve means and conduit means controlledthereby operable by movement of the contactor element to admit fluid pressure. from the source to the timing means to operate it.

5. In an electro-fluid-pressure system, a source of electric current, a source of fluid pressure, an apparatus having an electrically energizable circuit and a fluid pressure movable element, an electrically operable valve and conduit means controlled thereby for communicating source pressure to the apparatus element, electric contactor means comprising an element movable by fluid pressure to close andafter a predetermined time interval to open the energizing circuit, the contactor means comprising a fluid pressure chamber and conduit means for communicating source fluid pressure thereto under control of the electrically operable valve, fluid pressure operable timing means controlling energization of the valve to maintain it operated for a predetermined time interval' after opening of the energizing circuit, valve means and conduit means controlled thereby operable by fluid pressure effected movement of the contactor' element to admit fluid pressure from the source to the timing means to operate it, and an exhaust from the contactor fluid pressure chamber opened upon operation of the timing means to effect restoring of the contactor element. v

6. In an electro-fluid-pressurer system, a source of electric current, a source of fluid pressure, an

yapparatus having anenergizable electric circuit and a fluid pressure movable element, electricalf ly actuated means and means associated therethe energizing circuit, timing means controlling `the electrically actuated means to effect restor ing of the apparatus element andto prevent a successive movement thereof until after apredetermined time interval, and means responsive to movement of the contactor element to actuate the timing means.

'1. The system described in claim 6 and in which the timing means is a fluid pressure operated timing means and a valve and conduit means controlled thereby are provided, the valve being operated responsive to movement of the contactor element to communicate source fluid pressure to the timing means to operate it.

8. In an electro-fluid-pressure system, a source of .electric current, a source of fluid pressure, an apparatus having an energizing electric circuit and having a fluid pressure movable element, an electrically operable valve and conduit means controlled thereby fory communicating source fluid pressure to the apparatus element to move it, electric contactor means comprising a movable element movable to close and after a predetermined time interval of movement to open the energizing circuit, timing means controlling energization of the valve to eiIect restoring of the apparatus element and to prevent a successive movement thereof until after a predetermined time interval, and means responsive to movement of the contactor element to actuate the timing means.

9. In an electro-iiuid-pressure system, a source of electric current, a source of iluid pressure, an apparatus having an electrically energizable circuit and a iiuid pressure movable element, an electrically operable valve and conduit means controlled thereby for communicating source fluid pressure to the apparatus element to move it, electric contactor means comprising a movable element movable to close and after a predetermined time interval oi' movement to open the energizing circuit, iluid pressure cperated timing means controlling energization of the` valve to eil'ect restoring of the apparatus element and to prevent a successive movement thereof until after a predetermined time interval, a valve and conduit means controlled thereby operable by movement of the contactor ele-- ment to communicate fluid pressure from the source to the timing means to operate it.

10. In an electro-fluid-pressure system, a source of electric current, a source of fluid pressure, an apparatus having an electrically energizable circuit and a iluid pressure movable element, electrically actuated uid pressure means controlling movement of the apparatus element, electric contactor means comprising a movable and restorable element arranged, when moving, to close and then open the energizing circuit, fluid pressure operable means controlling the electrically actuated means and operable to maintain the apparatus element moved for a predetermined time interval after opening of the circuit, and then to effect restoring of the apparatus element, the timing means upon restoring controlling actuation of the electrically actuable means to prevent a successive movement of the apparatus element until after a predetermined time interval, means responsive to movement of the contactor element to operate the timing means and responsive to restoring of the contactor element to restore the timing means.

11. The system described in claim l and in which a valve and conduit means controlled thereby is provided and the contactor element upon moving effects operation of the valve to admit fluid pressure through the conduit means to the timing means tc operate it, and the contactor element upon restoring effects restoring of the valve to cut olf communication of the source pressure from the timing means and to exhaust the timing means to effect restoring thereof.

12. In an electro-fluid-pressure system, a source of electric current, a source of fluid pressure, an apparatus having an electrically energizable circuit and having a fluid pressure movable element, an electrically operable valve and conduit means controlled thereby for communieating source fluid pressure to the apparatus element, electric contactor means comprising a fluid pressure movable element movable to close and after a predetermined time interval of movement to open the energizing circuit, timing means controlling energization of the valve to maintain it operated for a predetermined time interval after opening of the energizing circuit, means responsive to movement of the contactor element to actuate the timing means, the timing means upon restoring controlling energization oi' the electrically operable valve to prevent a successive operation thereof until after a predetermined time interval, and means responsive to the restoring of the contactor element to effect restoring of the timing means.

13. In an electro-fluid-pressure system, a source of electric current, a source of fluid pressure, an apparatus having an electrically energizable circuit and having a fluid pressure movable element, an electrically operable valve and conduit means controlled thereby for communicating source pressure to the apparatus element, electric contactor means comprising a fluid pressure movable element movable to close and after a time interval of movement to open the energizing circuit, iluid pressure operated timing means controlling energization of the valve to maintain it operated for a predetermined time interval after openingof the energizing circuit, valve means and conduit means controlled thereby, the valve means being operated by movement of the contactor element toadmit source fluid pressure to the timing means to operate it, the timing means upon restoring controlling energization of the electrically operable valve to prevent a successive operation thereof until after a predetermined time interval, and the said valve means being restored upon restoring of the contactor element to effect restoring of the timing means.

14. In an electro-iluid-pressure system, a source of current, a source of fluid pressure, an apparatus having an electrically energizable circuit and having a fluid pressure movable element, an electrically operable valve and conduit means controlled thereby for communicating source fluid pressure to the apparatus element, contactor means comprising a fluid pressure movable element movable to close and after a predetermined time interval of movement to open the energizing circuit, fluid pressure operable timing means controlling energization of the valve to maintain it operated for a predetermined time interval after the opening of the energizing circuit, the timing means upon restoring controlling energization of the valve to prevent a successive operation thereof until after a predetermined time interval, valve means operated by movement of the contactor element and conduit means controlled thereby to effect communication of source pressure to the timing means to operate it, and the valve means controlling other conduit means and effecting restoring of the timing means upon restoring of the valve means by restoring of the contactor element, and the timing means upon operating effecting exhaust of pressure from the contactor element to effect restoring thereof.

ARTHUR B. SONNEBORN, 

